Producing high-frequency oscillations.



R. A. PESSENDEBL, PRODUCING HIGH FREQUENCY OSGILLATIONS. APPLICATIONFILED DEO.14,1905.

.932, 1 1 1 Patented Aug. 24, 1909.

FIELI- F|B-2 WITNESSES:

. V I M I r EQJNVENTGR BEGINAILD A. FESSENDEN, OF WASHINGTON, FIS'IRIGTOF COLUMBIA.

{PRODUCING HIGH-FEE QUENCY OSCILLAT IONS.

Specification 6: Letters Patent.

Patented Aug. 24', 1909.

Application filed lieoember 14, 1905. SerialNo. 291,739.

.To all whom it may concern: H

Be it'known that I, REGINALD A. FEssEN- DEN, a citizen of the UnitedStates, and resident of Washington, Districtof Columbia, have inventedcertain new and useful Imrovements in Producin High-Frequencyscillations, of which t e following is a specification. J

' The invention described herein relates to production of high frequencyoscillating currents, the currents 'so produced being especially adaptedfor the generation of electromagnetic waves for transmission of energy,particularly in wireless telegraphy and telephony. I

The invention is hereinafter more fully described and claimed.

In the accompanying drawings, forming a part of this specification,Figure 1 is a sectional elevation of a condenser havin a member movablerelative to the other; ig. 2 is a transverse section of the same; Flgs.3, 4, 5 illustrate modifications in the construction of the condenser,and Fig. 4 is a section of the structure of Fig. 4 on' line 4* therein.Fig. 6 illustrates a form of sending apparatus embodying my improvedcondenser, and Fig. 7 illustrates another formof sending a 'paratus.

It has eretofore been generally assumed as necessary for electromagneticor Wireless transmission of signals, to use a s ark-gap for producingoscillations, but I ave developed a system for the wireless transmissionof ener y in which a spark gap is not used and which has been found tobe not only more efficient as regards the use of power, but alsoentirely free from disturbing electrical effects, such as are producedby 40 atmospheric electricity or otherv stations and is capable of thevery highest degree of selectivity.

In the practice of my invention provision is made for bausing variationsin the amount of current flowing inan oscillating circuit by varying thecapacity of the circuit. This can e, effected by employing a condensercapab e-of having its capacity altered very ra idl thereby roducing verysudden P Y P changes ,lIlllhB amountpf current flowing in theoscillating circuit. Any suitable means may be employed for producin thedesired I rapid change of capacity, and

" inthe drawin s forillustration several means suitable or that purpose.

have shown In the construction shown in Figs. 1 and 2,

m'ay' be employed, consistin there is a condenser having one of itsparts or elements formed by a drum or cylinder, 1, having av series ofsuitably spaced projections, 2, arranged at an angle to the direction ofrotation of the drum, which is mounted on a shaft, 3, driven by asuitable motor, 4. 'A shell, 5, which may artially, but preferablywholly surround t e drum, is provided with a series of inwardrojections,'6, and is arranged concentric with the drum. Any suitabledielectric ma be employed as a solid insulating materia or compressedvair, or a vacuum may be maintained etween the two parts or elements ofthe condenser. It is preferred, however, to employ a cylinder, 7, ofmica, referably secured inside of the shell, 5. his mica acts as aninsulator and ermits a higher potential to be maintained between the twoparts or elements.

It will be understood by those skilled in the art, that members of thecondenser may both be rotated, in opposite directions,

thereby doubling the variations or changes of ca acity in-a given time.In-lieu ofxmaking t e condenser elements in the form of rojections onconcentric cylindrical suraces, the construction shown in Fig. 3, of twodisks or plates, ,8, provided with ra( ial ribs or projections, 9. Oneor both of these disks are provided with shafts, 10, whereby they may erotated in o osite directions as by bands 10*, 10 Wgfle any suitabledielectric may be employed, it is preferred to secure sheets, 11, ofmica on the adjacent faces of the disks for the double purpose ofavoiding air friction and furnishing a highly eificient insulation.

As shown in Fig. 4, I may use in lieu of one of the disks, 8, a sheet,29, of mica or glass, rubber or other suitable material, coated withmetal, as silver, and the coating or silvering is partially removed soas toform radial conducting strips corresponding to the radial ribs orprojections, 9, on the disk, 8 (see Fig. 4

It will be understood thattwo disks or plates of mica, etc.,"may beemployed advantageously, mounted to rotate as in Fig. 3, as on accountof their slight weight, they can be rotated at very highspeed.

It is evident that when the ribs or projections on the members of thecondenser are directly opposite each other, the capacity of the diskswith respect to each other, will be mum, and from minimum to maximum, as

The primaryy15, of the transformer is m the other member. members isfixed and the other movable, the

capacity will vary from maximum to. mini,-

many times per revolution, as there are ribs or projections on the fixedor movable mem-' her. If the ribs or projections on' the monk bers, forexample, are one-tenth of an'inch. wide and the spaces between adjacentribs also one-tenth of an inch wide, and thedisk in many ways, and theribs may be so shaped moves at a peripheral speed of twenty miles perminute, which I have ascertained is ob.- tainable, the ca acity bechanged through a comp ete cycle, one hundred thousand (100,000) timesper second and the electrical oscillations so reduced will be of thatfrequency. If bot members be retated one opposite the other, at theperiphe Ilephony. The mica disk, 29, with its eon ducting segments, isattached to a resilient- -diaphragm, 30, by fine platinum rods, 31. .Ontalking into the .mouth piece, 32, the

oral speed stated, the freriluency will be doubled, there being two 7undred thousand (200,000) cyclesper'second. I have ascertained that,contrary to what has been held by many experimenters, wireless t-elegraby can be carried on very efi1.-. ciently wit fre uenciesas low astwenty thousand (20,000 or second. This. corree s onds to a perip eralspeed when both Isks are rotatlng, of two miles er minute, and hencewith my improved mot ed, a very wide range of frequencies can beobtained. By the means described herein, it is possible to obtain morethan five hundred thousand (500,000) difierent fro ueneies, alLof whichcould act independent y ahd in close imity. I

Any convenient form: or arrangementof apparatus can be employed forutilizing the oscillations, As for eXample*,-in Fi 6, is shown a form ofa paratus in which the aerial, 12, is 'groun ed and is opcrativelyconnected to the secondary, 13, of the transformer, and to the variablecondenser, 14.

circuit of the source; 16, of voltage (prefers ably constantlwhich mayhave a number of dry or stor'a e cells. A capacity changer, '17, such asliereinbefore described, is also arranged in the circuit of the sourceof Y012. tage and the primary, 15. A condenser, 26, and an -inductance,.27, may also be usedif desired, in accordance with methods well knownin the art. In operation, when-the ribs on one member of the capacitchanger, are op osite the spaces between t e ribs on the v0t er 'member,the capacity will be; a minimum. When, during the movement of one orboth members, the ribs on the two members are opposite each other, thecapace 1ty will be maximum and the cur-rent flow into the disks andproduce an oscillation in the aerial.

When one of the condenser In 7, is shown another form of apps-.-

' mately sine form in the fluctuations. .is best done empirically,especially if the material.

grounded. .A continuous current generator,

as a dynamo, 28, is connected to the aerial and als to. ground. By theoperation of the capacity changer 17 in this arrangement,

the capacity of the aerial to ground is. i

changed every time the ribs on one member kpass the ribs on. the othermember of'the changer, and thereby set up an oscillation in the aerial-The capacity changer may lie constructed and proportioned as, to give anapproxi- This members are formed of coated insulating In Fig. 4, is.Shawna form of capacity changer especially adapted to wireless te disk,29, is caused to approach and recede from the rotating disk, 8, therebychanging the capacity and the strength of the oscillas tions inaccordance with the sound Waves vibrating the. diaphragm, 30.. I

In some cases, it. is preferred to arrange one part or member eccentricto the other, as

- shown in Fig. 5, in which the conducting ribs orportions are arrangedto be parallel or approximately so with the ribs or conduct-. ingportions on the other disk, when such ribs are moving adjacent. to thefirst disk.-

I claim herein as my invention:-

i 1. A capacity changer for electromagnetic electric circuits comprisinga condenser and means to rapidly move its, eflective eodperate ingmembers relative to each other, to produce oscillations in the circuit.

2. A high frequency oscillation producer comprising a condenser andmeans to very rapidly vary the relative distances apart of its effectivecondensing surfaces.

3. device for producing oscillations in a circuit comprising a condenserand means-to regularly and continuously vary its ca .a city at a veryhigh frequency, substantia as described. I

4. A wireless telegraph sending circuit including as a ca acity twoconductors separated by a die ectric, ,and means for .veryrapidlyvarying the distance between the effective areas of said ca acityconduct tors whereby to produce oscillations in the circuit by varyingthe-capacity.

5. An ap aratus forproducing high fr 'quency'osc ations in a circuit,comprising two condenserparts or elements movable relative to each otherwhereby to vary the.

current and oduce oscillations. B. An apparatusfor producing highfrequency oscillations in a circuit comprising a condenser and means tomove the effect ve .areas of one of its members rapidly with tions.

7. In an apparatus for producing high freuency oscillations, a circuitand a capacity hanger therein comprising a condenser With its membersmovable relative to each other, and means for moving said members withsufiiciently highfrcquency to produce electric oscillations.

8. A condenser comprising two members having on their adjacent faces'aseries of conandinsulated surfaces, a second member;

having alternate conducting and insulated portions, means to move onemember wlth respect to the.other, and means actuated by sound waves tomove the other member relativelyto the first, substantially asdescribed.

10. In Wireless telephone apparatus the combination with a condenser andmeans to rapidly move one of its members with respect to the other, of asound actuated element attached to and adapted to move one of theelements of the condenser with respect to the other, whereby to produceoscillations in a circuit and at the same time vary the strength of saidoscillations in accordance with sound waves substantially as described.

11. Means for' producing sustained electrical oscillations, of definitefrequency, comprising a circuit including a capacity, means for changingthe ca acity, and means for periodically altering the value of thecapacity very rapidly, substantially as described.

In testimony whereof I have hereunto set my hand.

. REGINALD A. FESSENDEN. Witnesses;

HELEN M. FEssENDEN, Jnssrn E. BENT.

